Scanning a colony is a good way to gather valuable information. You can scan a colony with tactical infiltration drones which return different information. Each infiltration drone requires a new research and facility to be completed in the Scans technology tree.

The success of the scan depends on your colony beacons and the target colony grids. Each upgraded grids level greatly increases the chance to block enemy scanning attempts. As a rule of thumb, you need to have two levels higher beacon than the target colony has it's grids to have a 100% success rate when scanning.

Success Rate = round(((beaconLVL * 9 + num_drones * 0.25)* PlanetProjectBeaconBonus)/((GridsLVL * 13)*PlanetProjectGridsBonus)*100)

If you receive a lower success rate than 100%, then the colony information is distorted. This means that each piece of information is multiplied with a random % between your success-rate and 100%. For example a success-rate of 82% means that each piece of information can be between 82% and 100% accurate.

If your success-rate drops below 60%, the colony will always be informed of your scanning attempts. If you receive a success-rate over 60%, then the colony has a 15% chance to notice your scan.